How severe is CVE-2023-51518?

CVE-2023-51518 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-51518?

CVE-2023-51518 affects the following packages: org.apache.james:james-server (Maven), org.apache.james:james-server (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-51518?

Update org.apache.james:james-server to 3.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-51518 is resolved across your whole dependency graph.

How do I detect CVE-2023-51518 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.james:james-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-51518 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2023-51518 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-51518 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-51518?

CVE-2023-51518 has an EPSS (Exploit Prediction Scoring System) score of 1.2%, placing it in the 68th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-51518?

CVE-2023-51518 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2023-51518 published, and has it been updated?

CVE-2023-51518 was published on February 27, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

CVE-2023-51518 — james-server

CRITICAL

CVE-2023-51518 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in org.apache.james:james-server. A fix is available for org.apache.james:james-server — see the affected versions and patch details below.

Apache James server: Privilege escalation via JMX pre-authentication deserialisation

Also known asGHSA-px7w-c9gw-7gj3

Published

Feb 27, 2024

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-51518.

EPSS Exploitation Probability

via FIRST.org ↗

1.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs68th percentile — riskier than 68% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

☕org.apache.james:james-server☕org.apache.james:james-server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

We recommend users to: - Upgrade to a non-vulnerable Apache James version

- Run Apache James isolated from other processes (docker - dedicated virtual machine) - If possible turn off JMX

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.james:james-server`	all versions	3.7.5`org.apache.james:james-server:3.7.5`
☕Maven	`org.apache.james:james-server`	≥ 3.8.0&&< 3.8.1	3.8.1`org.apache.james:james-server:3.8.1`

Affected Products

1 product · 2 configurations

Application

jamesapache

2 versions

3.7.53.8.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.james:james-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.james:james-server to 3.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-51518 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

Apache James prior to version 3.7.5 and 3.8.0 exposes a JMX endpoint on localhost subject to pre-authentication deserialisation of untrusted data. Given a deserialisation gadjet, this could be leveraged as part of an exploit chain that could result in privilege escalation. Note that by default JMX endpoint is only bound locally. We recommend users to: - Upgrade to a non-vulnerable Apache James version - Run Apache James isolated from other processes (docker - dedicated virtual machine) - If possible turn off JMX

O3 Security · Impact-Aware SCA

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CVSS Score

9.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE Classification

CWE-502Deserialization of Untrusted Data

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Feb 27, 2024

Last updated

Oct 28, 2026

Identifiers

CVE-2023-51518

GHSA-px7w-c9gw-7gj3

References

Advisorygithub.com · CVE 2023 51518.json Advisorylists.apache.org · wbdm61ch6l0kzjn6nnfmyqlng82qz0or Advisorynvd.nist.gov · CVE 2023 51518

Related vulnerabilities

This CVE is critical severity; 1 of 8 other CVEs affecting james-server is rated as high or higher (top: critical).

CVE-2023-51747CVE-2022-45935CVE-2022-28220CVE-2015-7611CVE-2004-2650CVE-2022-22931CVE-2021-40525CVE-2021-38542

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 28, 2026

CVE-2023-51518 — james-server

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2023-51518 in your dependencies?